TSPLIB: Questions and answers



Q: I found a better solution than the one claimed to be optimal in TSPLIB, is this possible?

A: This never occured so far. In all cases when someone believed to have found a better solution, it was not taken into account that it is exactly specified how distances for TSPLIB problems have to computed. Typical errors are
Q: I get wrong distances for problems of type GEO.

A: In a previous release there was a typing error in the distance specification for these problems. The formulae for computing latitude[i] and longitude[i] should read
Q: What does the function nint() do?

A: The function "int nint (double x)" converts x into int format rounding to the nearest int value, except halfway cases are rounded to the int value larger in magnitude. This corresponds to the Fortran generic intrinsic function nint.
Q: Are contributions still welcome?

A: Basically yes, but, in view of the many problem instances that are already available, new instances should either be real challenge problems or be of general interest.
Q: Is an optimal tour available for every solved problem instance?

A: No. We have included several optimal tours for testing purposes. It is not intended to provide all optimal tours. It should still be a challenge to find one.
Q: Are there optimal solutions available for instances other than symmetric ones?

A: So far, no other optimal solutions have been made available.


Last change: June 26, 1995